Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs
Dielectric metasurfaces supporting quasibound states in the continuum (quasi‐BICs) exhibit very high‐quality factor resonances and electric field confinement. However, accessing the high‐Q end of the quasi‐BIC regime usually requires marginally distorting the metasurface design from a BIC condition,...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley-VCH
2022-12-01
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| Series: | Advanced Photonics Research |
| Subjects: | |
| Online Access: | https://doi.org/10.1002/adpr.202200111 |
| _version_ | 1811205637172887552 |
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| author | Gianni Q. Moretti Andreas Tittl Emiliano Cortés Stefan A. Maier Andrea V. Bragas Gustavo Grinblat |
| author_facet | Gianni Q. Moretti Andreas Tittl Emiliano Cortés Stefan A. Maier Andrea V. Bragas Gustavo Grinblat |
| author_sort | Gianni Q. Moretti |
| collection | DOAJ |
| description | Dielectric metasurfaces supporting quasibound states in the continuum (quasi‐BICs) exhibit very high‐quality factor resonances and electric field confinement. However, accessing the high‐Q end of the quasi‐BIC regime usually requires marginally distorting the metasurface design from a BIC condition, pushing the needed nanoscale fabrication precision to the limit. This work introduces a novel concept for generating high‐Q quasi‐BICs, which strongly relaxes this requirement by incorporating a relatively large perturbative element close to high‐symmetry points of an undistorted BIC metasurface, acting as a coupler to the radiation continuum. This approach is validated by adding a ≈100 nm diameter cylinder between two reflection‐symmetry points separated by a 300 nm gap in an elliptical disk metasurface unit cell, using gallium phosphide as the dielectric. It is found that high‐Q resonances emerge when the cylindrical coupler is placed at any position between such symmetry points. This metasurface's second harmonic generation capability in the optical range is further explored. Displacing the coupler as much as a full diameter from a BIC condition produces record‐breaking normalized conversion efficiencies >102 W−1. The strategy of enclosing a disruptive element between multiple high‐symmetry points in a BIC metasurface can be applied to construct robust high‐Q quasi‐BICs in many geometrical designs. |
| first_indexed | 2024-04-12T03:35:32Z |
| format | Article |
| id | doaj.art-6a6d1683f6294602b405d73748f592c8 |
| institution | Directory Open Access Journal |
| issn | 2699-9293 |
| language | English |
| last_indexed | 2024-04-12T03:35:32Z |
| publishDate | 2022-12-01 |
| publisher | Wiley-VCH |
| record_format | Article |
| series | Advanced Photonics Research |
| spelling | doaj.art-6a6d1683f6294602b405d73748f592c82022-12-22T03:49:27ZengWiley-VCHAdvanced Photonics Research2699-92932022-12-01312n/an/a10.1002/adpr.202200111Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICsGianni Q. Moretti0Andreas Tittl1Emiliano Cortés2Stefan A. Maier3Andrea V. Bragas4Gustavo Grinblat5Departamento de Física, FCEN, IFIBA-CONICET Universidad de Buenos Aires Buenos Aires C1428EGA ArgentinaChair in Hybrid Nanosystems Nanoinstitute Munich Faculty of Physics Ludwig-Maximilians-Universität München 80539 München GermanyChair in Hybrid Nanosystems Nanoinstitute Munich Faculty of Physics Ludwig-Maximilians-Universität München 80539 München GermanyChair in Hybrid Nanosystems Nanoinstitute Munich Faculty of Physics Ludwig-Maximilians-Universität München 80539 München GermanyDepartamento de Física, FCEN, IFIBA-CONICET Universidad de Buenos Aires Buenos Aires C1428EGA ArgentinaDepartamento de Física, FCEN, IFIBA-CONICET Universidad de Buenos Aires Buenos Aires C1428EGA ArgentinaDielectric metasurfaces supporting quasibound states in the continuum (quasi‐BICs) exhibit very high‐quality factor resonances and electric field confinement. However, accessing the high‐Q end of the quasi‐BIC regime usually requires marginally distorting the metasurface design from a BIC condition, pushing the needed nanoscale fabrication precision to the limit. This work introduces a novel concept for generating high‐Q quasi‐BICs, which strongly relaxes this requirement by incorporating a relatively large perturbative element close to high‐symmetry points of an undistorted BIC metasurface, acting as a coupler to the radiation continuum. This approach is validated by adding a ≈100 nm diameter cylinder between two reflection‐symmetry points separated by a 300 nm gap in an elliptical disk metasurface unit cell, using gallium phosphide as the dielectric. It is found that high‐Q resonances emerge when the cylindrical coupler is placed at any position between such symmetry points. This metasurface's second harmonic generation capability in the optical range is further explored. Displacing the coupler as much as a full diameter from a BIC condition produces record‐breaking normalized conversion efficiencies >102 W−1. The strategy of enclosing a disruptive element between multiple high‐symmetry points in a BIC metasurface can be applied to construct robust high‐Q quasi‐BICs in many geometrical designs.https://doi.org/10.1002/adpr.202200111bound states in the continuumdielectric metasurfacesnanophotonicssecond-harmonic generation |
| spellingShingle | Gianni Q. Moretti Andreas Tittl Emiliano Cortés Stefan A. Maier Andrea V. Bragas Gustavo Grinblat Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs Advanced Photonics Research bound states in the continuum dielectric metasurfaces nanophotonics second-harmonic generation |
| title | Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs |
| title_full | Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs |
| title_fullStr | Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs |
| title_full_unstemmed | Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs |
| title_short | Introducing a Symmetry‐Breaking Coupler into a Dielectric Metasurface Enables Robust High‐Q Quasi‐BICs |
| title_sort | introducing a symmetry breaking coupler into a dielectric metasurface enables robust high q quasi bics |
| topic | bound states in the continuum dielectric metasurfaces nanophotonics second-harmonic generation |
| url | https://doi.org/10.1002/adpr.202200111 |
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